Extensive Introduction of Intermittent Renewables in Japanese Power system

The 4th Council Meeting of GJETCFeb. 15, 2018

Berlin, Germany

Yasumasa FujiiDepartment of Nuclear Engineering and ManagementUniversity of Tokyo

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Outline

Power system model for Japan• Formulation of the model• Case study for extensive introduction of variable renewable power

sources• Utilization of surplus electricity as heat source for direct air capture of

CO2

Concluding Remarks

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(Source) Compiled from “2010 Report of Wind Power Potential,” METI

5.5 m/s or more6.0 m/s or more6.5 m/s or more7.0 m/s or more7.5 m/s or more8.0 m/s or more8.5 m/s or more9.0 m/s or more

Potential onshore wind sites Annual average wind speed

Kyushu(29GW)

Chugoku(20GW)Kansai(42GW)

Shikoku(12GW)

Chubu(40GW)

Large Wind Resource

Endowment

Hokuriku(11GW)

Tokyo(83GW)

Tohoku(30GW)

Hokkaido(9GW)

Wind power generation is expected to increase in the future. (favorable sites are found particularly in Hokkaido and Tohoku.)

Hokkaido and Tohoku will employ power grids to balance the output fluctuations and surplus power of wind energy as well as stationary battery and the suppression control.

Tie Line Bottleneck

0.6~0.9GW

5GW

50 Hz

60 Hz

2~3GW

*Total Power Generation Capacity in Japan: about 270 GW

Potential of wind power integration in Japan 3

Japanese power system model 4

Normal Resolution Version

SimplifiedVersion

High Resolution Version

135 nodes166 branches

352 nodes441 branches

Hokkaido

Hokuriku

Chubu

KansaiChugoku

ShikokuKyusyu

0.9GW

5.0GW ↓1.5GW ↑

3.0GW

0.3GW1.6GW ↓1.3GW ↑

2.5GW →1.2GW ←

4.0GW →2.7GW ←

0.6GW ↓0.6GW ↑0.3GW ↓

2.8GW ↑1.4GW

Kanto

Tohoku

9 areas and 10 interconnection lineswith additional wind power transmission lines

Estimated solar and wind power 5

The time profiles of outputs of the intermittent renewables were estimated from meteorological data for each node at 10min interval.

Example of solar profile Example of wind profile

In the model, power from solar and Wind can be suppressed, if necessary（= Disconnection from the power system）

Electricity demand profile

• Time resolution of the original data in 2012 is 1 hour.• The demand allocation for each node was made on the basis of

IEEJ East 30 and West 30 models.

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60

85

110

135

160 GW Annual Load Curve

JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC

New Year Holiday

“Golden Week”

Summer Vacation

Min

Max

020406080

100120140160

0 2196 4392 6588 8784

GW

hours

Load Duration CurveMax: 154GW

Average: 104GW

Min: 66GW

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GW Power Load (20/JUL-26/JUL)Hokkaido Tohoku Kanto Chubu Hokuriku Kansai Chugoku Shikoku Kyushu

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GW Power Load (20/APR-26/APR)

Hokkaido Tohoku Kanto Chubu Hokuriku Kansai Chugoku Shikoku Kyushu

Outline of the model

• Geographical Coverage and Resolution• Entire Japan excluding Okinawa and small islands• The power system is modeled as a network of 9 nodes.

• Temporal Coverage and Resolution• Entire year at one hour interval

• 8,760 time points for normal year

• Modeling Approach• Cost Minimization with Linear Programming

• The number of variables and constraints is around 5 millions.• It takes one hour to obtain an optimal solution with CPLEX.

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Major variables in the model

• Types of power generation• Nuclear power plants• Fossil fuel-fired power plants

• Coal-fired, Gas combined cycle, Gas-fired and Oil-fired• Non-intermittent renewables

• Hydro, Geothermal, Biomass-fired and Marine energy• Intermittent renewables

• Wind and Solar• Types of electricity storage

• Pumped hydro storage• Battery

• Longer-period storage battery (Na-S battery)• Shorter-period storage battery (Li-ion battery)

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Example of simulation analysis for Japan 9

‐200

‐100

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Power Gen

eration [GW]

Suppressed WindSuppressed PVBattery(in)Pumped(in)Battery(out)Pumped(out)WindPVOilLNGLNG GCCCoalNuclearGeothermalHydroDemand

Optimal Power Dispatch in Japan (May) (PV ratio(kWh):20%, Wind ratio(kWh):10%)

(Source) R.Komiyama,Y.Fujii, IEEJ Transaction B,Vol.132,No.7,pp.639-647,2012

May 1

May 31

Optimal Power Dispatch in Tohoku (May) (Wind ratio(kWh):10%)

‐30

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0

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50

Power Gen

eration [GW]

Hokkaido→TohokuTohoku→HokkaidoKanto→TohokuTohoku→KantoSuppressed WindSuppressed PVBattery(in)Pumped(in)Battery(out)Pumped(out)WindPVBaiomassOilLNGLNG GCCCoalNuclearGeothermalHydroDemand

May 1

May 31

(Source) R.Komiyama,S.Shibata,Y.Fujii, IEEJ Transaction B,Vol.133,No.3,pp.263-270,2013M

ay 10

May 20

May 10

May 20

PV

Suppression(PV) Wind Suppression(Wind)

NAS Battery(charge)Pumped-hydro

LNGCC

WindSuppression(Wind)

NAS Battery(charge)Pumped-hydro Power Interchange(Tohoku→Kanto)

NAS Battery(discharge)

Pumped-hydro

Pumped-hydroPVSuppression(PV) NAS Battery(discharge)

LNGCC

Options for extensive integration of VRE

1. Quick load following control by thermal power plant (e.g.

LNGCC)

2. Reinforcement of transmission capacity of networks

3. Demand-side management (demand extension(EV, heat-

pump water heater),BEMS, HEMS)

4. Suppression control (PCS, Interactive communication)

5. Energy storage such as electricity storage(Li-ion, NaS

etc.), pumped-hydro, hydrogen storage, heat storage etc.

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Assumed system to use surplus electricity 11

Electricity

Heat

WaterElectrolysis

H2Storage

Hydrogen

Water

MIT FIRES(Firebrick Resistance-Heated Energy Storage)

FluctuatingElectricity Constant Heat

Output

HeatDemand

ElectricityDemand

CapturedCO2

CO2 Storage

Atmospheric CO2

http://carbonengineering.com

DAC

Fischer-Tropsch

with reverse shift reaction

FuelDemand

ThermalPower

Generation

Non-fossilPower Generation

Chemical reaction of DAC system 12

Robert Socolow et al., Direct Air Capture of CO2 with Chemicals,The American Physical Society, 2011

900℃

Assumptions of sensitivity analysis 13

・Demand and supply balance of jet fuel

oil synoil FUEL 8MTOEo 80MTOE

・CO2 emission constraint2 2 2

2 2 2

CO2 emission factor = 0.76 t-C/TOE

Time step 1 hour

Area Aggregate 1 node in each area (9 areas)

HTGR Min cap: 0 GW, Max Cap: 11 GW

LNG GCC Each node: Max 20 GW

RE potential Wind: 260 GW, PV: No upper limit

Grid (new) Wind connecting line 1〜4, Kita-Hon line, Tohoku-Kanto line, FC

Nuclear upper limit 26GW or No upper limit

Liquid Fuel demand 8 MTOE of Jet fuel

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No CO2Limit

200Mt 150Mt 100Mt 50Mt 0Mt 0MtwithoutNuclearcap

Total C

ost (Trillion JPY/year)

Shad

ow Pric

e (10,00

0JPY/t‐CO2)

Electricity

 Gen

eration (TWh/year)

Net Heat & H2 UseSuppressed PVSuppressed WindBattery2(out)Battery1(out)Pumped(out)Battery2(in)Battery1(in)Pumped(in)PVWindHTTROilLNG GCCLNG STCoalNuclearMarineBiomassGeothermalHydroTotal CostShadow Price of CO2

Electricity generation and system cost 14

(302Mt)

0

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No CO2 Limit 200Mt 150Mt 100Mt 50Mt 0Mt 0Mt Nuc8MTOE synoil

Power Gen

eration Ca

pacity (G

W)

H2FIRESBattery2Battery1PumpedPVWindHTTROilLNG GCCLNG STCoalNuclearMarineBiomassGeothermalHydro

Power generation capacities 15

(302Mt)

Estimated synthetic fuel costs 16

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150Mt 100Mt 50Mt 0Mt 0Mt Nuc8MTOEsynoil

Fuel Produ

ction (M

TOE/year)

Unit Prod

uctio

n Co

st of S

ynthetic Fue

l (JP

Y/kg) H2 Cost

CO2 Cost

Electricity Cost

Fixed Cost

Fuel Production

Concluding remarks

• The larger share of VRE is estimated to enhance the use ofFIRES (Heat storage), and FIRES can enable us to utilizefully surplus electricity generated by VRE. Heat storageshould be paid more attention as an inexpensive energystorage technology.

• The unit cost of synthetic fuel production with FIRES, DACand WEL is estimated to be around 200 JPY/kg, and thefuel may be economically competitive against some typesof bio-jet-fuels made from algae. Such synthesizedhydrocarbon fuels can be one of promising energy carrierseven under stringent CO2 emission constraint.

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